National Repository of Grey Literature 48 records found  beginprevious28 - 37nextend  jump to record: Search took 0.01 seconds. 
Specific features of streptomycetes isolated from human tissues
Kodatová, Anežka ; Petříčková, Kateřina (advisor) ; Zikánová, Blanka (referee)
This bachelor thesis focuses on activities of the bacterial genus Streptomyces in relations to plants, animals and human. Many cases of their symbiotic relationships with plants are known, but there is also a common plant pathogen S. scabies. As a primary soil bacteria, their association with animals is infrequent, but not exceptional. Symbiotic relationships have been observed for example in several insect species. Streptomyces have been repeatedly isolated from the human microbiome, however only a little information about their influence on human body is available. Due to the wide production of secondary metabolites affecting other microorganisms, their role can be assumed as significant. The relationship between human Streptomyces and human could have a parallel in the Streptomyces symbiosis with plants and insects, but it can also have certain effects on pathogenesis. The ability of beta haemolysis was demonstrated in tested strains. In addition, there are cases of serious diseases caused by Streptomyces. Next to the relatively common actinomycosis in the regions of Sudan and India, diseases such as pneumonia or abscess were reported.
Evoluce genomu bakteriálních symbiontů vši \kur{Polyplax serrata} (Phthiraptera, Anoplura)
ŘÍHOVÁ, Jana
Blood-sucking louse Polyplax serrata harbor two phylogenetically distinct symbiotic bacteria from the orders Legionellales (Gammaproteobacteria) and Neisseriales (Betaproteobacteria). Based on rigorous phylogenetic analyses, the first bacteria was confirmed as member of genus Legionella, and the name Candidatus Legionella polyplacis, sp. n. was proposed. Vertical transgeneration transmission was proved by visualisation of the symbiont in host tissues. Improved genome of latter symbiont is considerably larger and possesses more metabolic functions. In the genome, I found horizontally transferred operon, which encode synthesis of enzymes involved in urea cleavage.
Dynamics of a lichen symbiosis
Vaiglová, Zuzana ; Škaloud, Pavel (advisor) ; Vondrák, Jan (referee)
The symbiotic relationships often represent not only the permanent cohabitation of two organisms, but they can evolve and change over time. Many papers published so far focused on the the specificity of lichens, characterising both highly specific species and those that can establish a symbiosis with many algal genotypes. In this second case we can imagine the possibility of a photobiont exchange during the life of lichen - the dynamics of lichen symbiosis. In this thesis I compared the occurence and diversity of photobionts within the thalli of lichens growing on the disturbed localities and on the the localities without the disturbance. These two types of localities were similar to species richness of photobionts, but the disturbed localities dominated by the number of photobiont genera. These localities also reached a higher value of phylogenetic diversity. Conversely, non-phylogenetic analysis revealed the higher level of photobiont diversity on non-disturbed localities, where the core of diversity was formed by different lineages of Trebouxia. I have also found the lichens, which cooperate with different algae on disturbed and non-disturbed localities. The photobiont distribution presented in this paper shows the possibility of photobiont exchange during the community succesion. The...
Utilization of cellulose and hemicellulose as a source of energy by symbiotic protists and other organisms
Hammerbauerová, Iva ; Tachezy, Jan (advisor) ; Hrdý, Ivan (referee)
In this thesis I focus on the enzymatic degradation of plant structural polysaccharides cellulose and hemicellulose. I describe the enzymes involved in their lysis and their breakdown and their function and occurence among organisms. I also pay attention to the mechanisms of xylose and arabinose catabolism as pentoses found in hemicellulose. I describe some niches where cellulose and hemicellulose degradation takes place and organisms that take part in it. Finally I shortly point out the biotechnological importance of these organisms in the production of bioethanol.
Prokaryotic symbionts of free-living anaerobic protists
Poláková, Kateřina ; Čepička, Ivan (advisor) ; Hampl, Vladimír (referee)
Anaerobní prvoci jsou organismy obývající ředí bez přítomnosti kyslíku. Najdeme je anoxických habitatech jako jsou mořské a sladkovodní sedimenty, komunální skládky, nesmíme opomenout zástupce žijící v bachoru přežvýkavců, trávicím traktu švábů a dalších živočichů. Většinou mají anaerobní deriváty mitochondrií, často hydrogenosomy, organely produkující vodík. Metabolismus anaerobních prvoků je ve srovnání s aerobními organismy méně efektivní Časté interakce anaerobních ický my však mohou Symbiózy mezi anaerobními běžné a vznikly u zástupců mnoha anaerobních linií. žít buď endosymbioticky, uvnitř buňky hostitele, nebo ektosymbioticky, na povrchu hostitelské buňky. Dvě ekologicky významné skupiny prokaryot si dokázaly osvojit život symbiotickém vztahu volně žijícími anaerobními prvoky anogenní archebakterie, osídlující hlavně , využívají vodík nické sloučeniny k anu a síran redukující bakterie, žijící hlavně na povrchu buněk, využívají vodík a různé organické sloučeniny k redukci síranu na sulfan. Velmi málo se ví o bližším charakteru těchto vztahů druhové identitě a hostitelské specifitě prokaryotických symbiontů. Další výzkum je nutný pro pochopení fenoménu symbióz v anoxickém světě. Klíčová slova: anaerobní prvoci symbióza anogenní archebakterie síran redukující bakterie
The phenomenon of symbiosis and its importance to theoretical biology
Lhotský, Josef ; Markoš, Anton (advisor) ; Neustupa, Jiří (referee) ; Krajčovič, Juraj (referee)
7 Abstract Close physical interspecific associations called symbioses are central for understanding both evolution and interactions of all branches of living creatures, as well as shaping the Earth's physical features - in other words, they are essential for understanding the nature of whole biosphere. Symbiotic research takes place in some variation in all fields of biology, and since the nature of the phenomenon apparently has a fundamental importance as an exceptional underlying & unifying scheme, there is growing need for appropriate theoretical analysis. Here I discuss the theoretical frame, definition and history of the concept of symbiotic interactions and its significance and use in theoretical biology. Keywords: symbiosis, life, microorganisms, evolution, metaphors and models
The phenomenon of symbiosis and its importance to theoretical biology
Lhotský, Josef
7 Abstract Close physical interspecific associations called symbioses are central for understanding both evolution and interactions of all branches of living creatures, as well as shaping the Earth's physical features - in other words, they are essential for understanding the nature of whole biosphere. Symbiotic research takes place in some variation in all fields of biology, and since the nature of the phenomenon apparently has a fundamental importance as an exceptional underlying & unifying scheme, there is growing need for appropriate theoretical analysis. Here I discuss the theoretical frame, definition and history of the concept of symbiotic interactions and its significance and use in theoretical biology. Keywords: symbiosis, life, microorganisms, evolution, metaphors and models
The role of trehalose in mycorrhizal associations
Šoch, Jan ; Ponert, Jan (advisor) ; Hála, Michal (referee)
Mycorrhizal symbiosis is a widely spread phenomenon in nature. A translocation of nutrients occurs between symbionts with disaccharide trehalose playing a key role in the process. However, this saccharide fulfils many important roles in metabolism of fungi and plants. Fungi use trehalose mainly as storage and transport saccharide. On the other hand, trehalose occurs in extremely low amounts in plants where it acts as a signal molecule. Thus it is likely that the saccharide could be used by the fungus to manipulate plant metabolism on a physical interface between symbionts. Trehalose has a similar function in many parasitic interactions. In most cases of mycorrhizal associations trehalose synthesis creates a carbon sink in mycelium which leads to saccharide transfer from the host plant to the fungus. Completely different situation occurs in the types of mycorrhizal symbiosis, where saccharides are translocated from a fungus to a plant. Some plants can utilize trehalose effectively as a sole source of energy. Consequently, the question raises - could such plants gain fungal trehalose on purpose as a source of energy and carbon? This review aims to assess and discuss the mentioned possibilities considering available literature. Key words: mycorrhiza, orchids, parazitism, saccharides, sink, symbiosis,...
Diverzita mikrobiomů vybraných druhů ovádů (Diptera: Tabanidae) a její vliv na přenos trypanosom \kur{(Trypanosoma sp.)}
SVOBODOVÁ, Simona
Three different bacterial symbionts have been known from blood-sucking horse flies (Tabanidae), Spiroplasma from family Spiroplasmaceae, Midichloria from family Midichloriaceae and Wolbachia from family Rickettsiaceae. Microbiomes of tabanids has been explored only marginally, therefore in my thesis I explore them in more details. I have described microbiomes of 7 species from Africa, USA and Czech republic, and found them to contain bacteria from families Spiroplasmataceae, Chthoniobacterales, Pseudomonadaceae, Acetobacteraceae, Enterobacteriaceae, Flavobacteriaceae, Staphylococcaceae, Halomonadaceae, Moraxellaceae. In addition, I have studied Trypanosoma´s influence on the compositon to the horse fly microbiome. I have not found significant differences between microbiomes of infected and uninfected individuals, indicating that the presence of Trypanosoma may not have any strong effect on the microbiome.
Biogeography and specificity of Asterochloris photobionts
Řídká, Tereza ; Škaloud, Pavel (advisor) ; Vondrák, Jan (referee)
This diploma thesis has focused on the diversity and biogeography of Asterochloris photobionts. Since no study so far has been published on the biogeography of symbiotic microorganisms, the presented thesis is the first attemp to trace the biogeographic distribution and endemism of symbionts. By gathering 121 Asterochloris sequences obtained from lichen thalli sampled outside Europe and America, the diversity within the genus increased dramatically. The phylogenetic analysis based on the concatenated alignment of ITS rDNA and actin sequences obtained from Cladonia and Stereocaulon photobionts revealed 28 differently supported clades. Of them, eight lineages were newly discovered. Three environmental factors explaining the best the distribution pattern of Asterochloris photobionts were selected according to the statistical tests of the phylogenetic signal: two different types of biogeographical ecoregions and the substrate type. In general, the genus Asterochloris is distributed cosmopolitally, with a very low rate of endemism. Newly obtained data indicate that the restricted distribution of any photobiont clade is not caused by either historic or biological factors, but more likely by specific climatic or habitat preferences.

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